Authorities imposed restrictions in various areas here on Friday to prevent separatist-called protests to mark the Accession Day of Jammu and Kashmir to India.Joint resistance leadership (JRL) of separatist leaders -- Syed Ali Shah Geelani, Mirwaiz Umer Farooq and Yasin Malik -- have asked people to observe October 27 as a "black day" in Kashmir.It was on this day in 1947 that the Indian Army landed in Srinagar Airport following the accession of the state."Restrictions under section 144 of CrPC will remain in force in Nowhatta, M.R.Gunj, Safa Kadal, Rainawari, Khanyar, Kralkhud and Maisuma," a police officer said.Heavy contingents of the state police and Central Reserve Police Force (CRPF) in full riot gear were seen disallowing pedestrian and vehicular movement in these areas.Railway services in the valley have also been suspended on Friday as a precautionary measure.